As a seat structure, there is a structure in which a thickness of a seat side portion is made flexible by left and right seat side portions of a seat cushion being made movable to a high position and a low position relative to a central top panel portion (for example, see patent reference 1).
However, in this seat structure, a support wire that supports the seat side portion from a reverse side is only urged toward a face side of the seat cushion by a torsion spring. Moreover, a turning plane of the support wire (a plane including a turning direction) is made perpendicular to a front-rear direction of the seat cushion. Therefore, a support rigidity of the seat side portion from the support wire with respect to a load in a left-right direction of the seat cushion is low.    Patent reference 1: Japanese Patent Application Laid-Open (JP-A) No. 2000-316663